Altium Slots

The slots are done in a different step than the via drilling. $ endgroup $ – Some Hardware Guy Dec 14 '12 at 3:13 $ begingroup $ Humm ok.I just feel unconfortable with so many different ways to interpret a PCB and repesent a slot.and OSH Park dont show them, unless you put it on the board edge layer I think $ endgroup $ – mFeinstein. Component placement & routing in Altium Designer. Find the complete course at: In Altium I have created a square slot in PCB then I create the gerber files. In CAM, file's square slot is shown as round shape. Can anyone explain why? Also I have enabled the G85 command.

Altium Designer is a professional PCB design tool.

Design Rule Setup

Downloadable Files

Kind customers have provided loadable DRC rule and Stackup files for our 2 and 4 layer services.

Note, these files are not exhaustively validated or guaranteed by OSHPark, and may contain errors. Use your judgment and always verify your designs meet our service specs to prevent design defects that could affect your boards. If you have corrections or find errors, please email support.

known issues: Current minimum 2 layer specs are 10 mil drill hits, with 5 mil annular rings. I think my son has a gambling problem now. The RUL file currently shows the older 13mil drill and 6mil ring

Generating Manufacturing Files

For accessing the various menus and output screens, see Altium’s Gerber Setup

Disabling “ Mechanical Layers to Add to All Gerber Plots”

Altium tools have the option Mechanical Layers to Add to All Gerber Plots, which must have all layers unchecked. Many footprints contain mechanical “courtyard” or “pick and place” data on these layers. When these footprints are added to copper layers, it can create gerbers that will be fabricated with shorts. See Altium’s Gerber Setup for information on how to access this setting.

Download Altium schematic symbols, footprints & 3D models for millions of electronic components only at SnapEDA. Altium’s native Slot callout is supported. See our slots slots guide for limitations and DRC requirements of slots.

Internal Plane Polarity

Altium slots games

We recommend submitting planes with a Positive polarity. See our Positive vs Negative Gerbers page for additional information.

Board Outline

We need a watertight board outline on its own layer with no extra text or measurements. This tells us where the fab should mill the edges of the board. This layer can also contain board cutouts.

For best results, place the outline by itself on the Keep Out, or on a Mechanical Layer (normally 1 or 2). This will generate the outline on .GKO or a .GM<number> file.



Drill files should work without issues for most export options. If the drill files do not appear correct, check out our Drill File CAM configuration page for settings that we know will work correctly.


Altium’s native Slot callout is supported. See our [slots][slots] guide for limitations and DRC requirements of slots.

Common Issues

Altium Slots

Missing Drill File

Altium keeps the drill data in the project-name.TXT file. Make sure any uploaded zip files include this file.

Drill file not being read correctly

Altium Slots Free

Try exporting the drill file with the INCH units. Some format issues in METRIC are more difficult to reliably correct.

Internal Layer names

If you’re using a 4 layer stackup with both “power” and “signal” internal layers, Altium will generate the internal layers as GP1 and G1. Unfortunately, this makes it impossible for us to determine the correct layer order, since multiple layers identify themselves as “Internal Layer 1”.

Slots In Altium

To correct this, simply rename the layers using the G2L and G3L extensions. The G2L will be near the Top Copper Layer, and G3L will be near the bottom layer.